There is a clear need to develop improved tools to stratify risk in patients who seek emergency care for chest pain, one of the most common and potentially deadliest conditions encountered in acute care settings. The ECG has been the mainstay of initial evaluation of chest pain patients, yet is currently only diagnostic for a small subset of patients with ST-elevation myocardial infarction. Prior studies have identified candidate markers of ECG characteristics and preliminary algorithms that can identify patients with non-ST elevation myocardial infarction as well as those with very low risk of coronary artery disease. This study will enroll a cohort of consecutive chest pain patients needed to confirm the accuracy of these ECG markers and determine their maximal clinical utility as part of a risk stratification tool. With these improved tools, emergency providers (physicians, nurses, and paramedics) will be able to streamline the care provided to these patients beyond the costly and time-consuming overnight observation for serial cardiac enzymes and provocative testing.

The disease burden of coronary artery diseases (CAD) remains one of the most serious and persistent health problems for the investigator's nation. One out of every six deaths in the United States is solely attributed to CAD. Every year, nearly 7 million adults visit the emergency department (ED), reporting chest pain associated with a possible heart attack. Being able to immediately differentiate between cardiac (ischemic) and non-cardiac chest pain is crucial and improves survival and reduces disability for thousands of people. The electrocardiogram (ECG) is an indispensable tool to detect ischemia and is the first tool available for initial chest pain evaluation in EDs and, even earlier, by paramedics in the field. Current guidelines focus on ST elevation (STE) to identify patients most in need of immediate treatment. Unfortunately, STE only occurs in one-third of all patients with acute myocardial infarction, and missed myocardial infarction remains one of the highest sources of medical malpractice in emergency medicine. This translates to delayed treatment for nearly 1 million heart attacks until costly, time-consuming, and more invasive diagnostics are conducted and interpreted. Prior work by the investigators has explored novel ECG markers, other than STE, and noted that the dynamic ECG changes in these markers can improve diagnosis of acute coronary syndromes (ACS). This prior data showed that myocardial ischemia disturbs the ventricular repolarization process and results in quantifiable distortions of T waves on the surface 12-lead ECG prior to any displacement of the ST segment. Markers of T wave abnormalities, therefore, can identify patients with ischemic chest pain in the absence of acute ST changes very early in the triage process. The current study plans to evaluate how these novel ischemic ECG changes evolve over time during the acute phase of the coronary syndromes. This approach has a high potential for improving the speed and accuracy of diagnosing ACS and is potentially deployable in any ED or ambulance to greatly accelerate definitive treatment, thereby reducing morbidity and mortality for thousands of patients each year.

Inclusion Criteria:

• (1) 18 years of age or over; (2) present with a chief complaint of non-traumatic chest pain or other atypical, suspicious symptoms requiring ECG evaluation (e.g., shortness of breath); and (3) arrives at ED by EMS transport with 12-lead ECG already obtained.

Exclusion Criteria:

• (1) those with traumatic chest pain; (2) those arriving at the ED by private means without prehospital ECG.

The proposed study is a prospective observational cohort study that will include consecutive patients in Pittsburgh, PA who call 9-1-1 with a chief complaint of chest pain.